1. Field of the Invention
The present invention relates to the field of posture chairs which are various configurations for seating arrangements that are used to improve the posture of the individual by more efficiently supporting the weight of the individual who sits on the seat and adjusting the height of the seat sections to accommodate movement of the individual in the seat.
2. Description of the Prior Art
In general posture chairs and various seat configurations used as an integral part of the posture chair are known in the prior art. The present inventors are pioneers in having developed and patented several seating arrangement which help to provide greater comfort to individuals as they sit on a seat. The following patents have been issued to either inventor Joseph A. Berg individually or to co-inventors Joseph A. Berg and Loren W. Eames.
1. U.S. Pat. No. 2,799,323 issued to Joseph A. Berg on July 16, 1957 for "Self-Aligning Seat Construction".
2. U.S. Pat. No. 3,080,195 issued to Joseph A. Berg on Mar. 5, 1963 for "Self-Aligning Seating Construction".
3. U.S. Pat. No. 3,749,442 issued to Joseph A. Berg and Loren W. Eames on July 31, 1973 for "Seat Having Relatively Adjustable Sections".
4. U.S. Pat. No. 4,047,757 issued to Joseph A. Berg and Loren W. Eames on Sept. 13, 1977 for "Seating Structures With Flexible Backs".
In each of these patents, the object was to provide a seat construction which readily responds to or accommodates itself to the position of the body of the person occupying it. The object was to provide a seat which was self-aligning and which was so constructed that it allowed each side of the body of the occupant of the seat to move normally and independently of the other without restraint.
U.S. Pat. No. 2,799,323 provided an embodiment with two separate seat halves which were independently supported by coil springs.
U.S. Pat. No. 3,080,195 was an improvement on U.S. Pat. No. 2,799,323 and comprises a seat having two independent halves wherein the flexibility is provided through a resilient cushion under each of the seat sections.
U.S. Pat. No. 4,047,757 discloses a seating unit with a flexible seat back having an upper portion separated into two halves positioned to support a user's back at opposite sides of his spine.
U.S. Pat. No. 3,749,422 was a substantial mechanical improvement on the concept embodied in the prior two U.S. Pat. Nos. 2,799,323 and 3,080,195. In this patent, the invention involved a seat assembly having a base and two complementary seat elements supported thereon. Each seat element was able to move independently of the other seating element. Each seat pad was supported by a universal joint support which permitted each seat to move in any tilting orientation to accommodate different positions of the user's body. Each seat element had recesses or apertures offset rearwardly from the universal connections for receiving the ischial tuberosity bones of the user, and the back of the seat had a localized recess for partial reception of the lumbar portion of the user's backbone.
While the seat having adjustable sections as disclosed and claimed in U.S. Pat. No. 3,749,422 had many beneficial effects, one disadvantage which has been discovered through extensive use of the seat is that the universal support which provided free tilting movement of each seat section in any multiplicity of directions in fact provides too much free movement, thereby resulting in fatigue of the user after about an hour of use. Therefore, to correct this problem with the prior art seating arrangement disclosed in U.S. Pat. No. 3,749,422, it is necessary to cut down on the fully universal movement of the seat halves. Various other posture seating and seat arrangements are known in the prior art and the following patents are representative of such arrangements:
1. U.S. Pat. No. 1,990,661 issued to Middleton in 1935 for "Vehicle Seat".
2. U.S. Pat. No. 4,589,699 issued to Dungan in 1986 for "Sit-Kneel Chair".
3. U.S. Pat. No. 663,087 issued to Johnson in 1899 for "Chair".
4. German Offenlegungsschrift No. 35 13 985 Al. This was published in 1986.
The U.S. Pat. No. 1,990,661 to Middleton relates to a Vehicle Seat and is of interest as being disposed upon a plurality of spherical members 7. However the spherical members do not have a front and back locking and rocking arrangement.
U.S. Pat. No. 4,589,699 to Dungan is for the well known Sit-Kneel Chair and discloses a pivotally mounted seat 7. However, movement is dependant upon a single bolt 50 as opposed to the sphere and pin locking and rocking arrangement.
U.S. Pat. No. 633,087 issued to Johnson shows a chair including a seat F which may tilt forward and rearward. However, the mechanism which consists of an arc shape support block G is different than the present invention arrangement.
Finally, German Patent Publication issued in 1986 shows a tilting chair of interest with respect to the Ball 6. However, the tilting is performed by a spring 7 and not by a locking and rocking arrangement.
Therefore, there is a need for an improvement on the seat having relatively adjustable sections as disclosed in U.S. Pat. No. 3,749,442 which will permit each of the seat halves to move independently of each other but in a modified manner which will restrict the totally universal movement of the seat as disclosed in this prior art patent, to thereby enable individuals to have more effective use of the seating arrangement without too much free universal movement and thereby reduce the fatigue created by the prior art seat. There is also a further need for a pivotal support which provides these functions and also has some vertical play therein to enable the user to have the seat moved vertically downward when the user sits on it.